Self-lubricating high-pressure plunger pump sealing ring and manufacturing method

Abstract

The invention relates to a self-lubricating high-pressure plunger pump sealing ring which comprises a head ring, a pressure ring and an isolating ring which are sequentially arranged on a plunger in a sleeving mode. The top of the head ring is provided with a herringbone protruding structure protruding outwards. A herringbone groove structure matched with the herringbone protrusion structure is arranged at the bottom of the pressure ring. The top of the pressure ring is provided with a cambered surface structure protruding outwards. And the cambered surface structure is matched with an arc-shaped groove formed in the bottom of the isolating ring. The invention further relates to a method for manufacturing the self-lubricating high-pressure plunger pump sealing ring. The head ring is suitable for extreme working conditions of high-pressure and high-hardness sand abrasion and high-acidity, low-viscosity and poor-self-lubricating fracturing fluid and cement paste corrosion, the performance of the head ring is remarkably improved, the service life of a fracturing packing assembly is prolonged, the operation cost and risk are reduced, and the oil and gas exploitation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well operation, and in particular to a self-lubricating high-pressure plunger pump sealing ring and a manufacturing method thereof. Background Art

[0002] Oilfield fracturing trucks are key equipment in oil and gas well production enhancement operations. They mainly use hydraulic fracturing technology to cause cracks to form in the oil and gas layers, optimize the underground flow of oil and gas, and thus increase the production of oil and gas wells. On the other hand, oilfield cementing trucks play an important role in oil and gas drilling operations. The high-pressure pumping system they are equipped with is used to pump cement slurry into the annular space between the casing and the well wall in the wellbore, fix the casing and seal off the unnecessary oil and gas layers or water flow layers, ensuring the safe production of oil and gas wells. As the core components of these vehicles, the performance of fracturing pumps and cementing pumps directly affects the operating effect of the entire equipment.

[0003] In the hydraulic end of fracturing pumps and cementing pumps, the packing assembly is a key component to ensure continuous power, and its life becomes an important indicator to measure pump performance.

[0004] The defects of the prior art are:

[0005] 1. Since fracturing pumps and cementing pumps work in extremely harsh environments, they are subject to high pressure, high hardness sand wear, and corrosion from fracturing fluids or cement slurries with high acidity, low viscosity, and poor self-lubrication. This causes packing components, especially rubber head rings, to be easily worn and corroded, thus shortening their service life. Frequent replacement not only increases operating costs and risks, but also affects oil recovery efficiency.

[0006] 2. In order to improve the wear resistance and corrosion resistance of the rubber head ring, some improvements have been made in the existing technology, such as changing the material of the rubber head ring from NBR to HNBR. HNBR material can effectively reduce the friction coefficient and wear and extend the service life of the head ring due to its better temperature resistance and chemical corrosion resistance. However, since the existing pure rubber head ring still has a large gap in wear resistance, tear resistance and corrosion resistance compared with the fabric reinforced rubber head ring, this limits its application effect and durability under extreme working conditions. Summary of the invention

[0007] In response to the above-mentioned problems, the present invention provides a self-lubricating high-pressure plunger pump sealing ring and a manufacturing method, with the purpose of providing a new type of packing head ring, which is particularly suitable for extreme working conditions of high pressure, high hardness sand wear and corrosion of fracturing fluid and cement slurry with high acidity, low viscosity and poor self-lubrication, significantly improving the performance of the head ring, extending the service life of the fracturing packing assembly, reducing operating costs and risks, and improving oil and gas production efficiency.

[0008] To solve the above problems, the technical solution provided by the present invention is:

[0009] A self-lubricating high-pressure plunger pump sealing ring comprises a head ring, a pressure ring and an isolation ring which are sequentially sleeved on the plunger, wherein:

[0010] The top of the head ring is provided with a herringbone convex structure protruding outward; the bottom of the pressure ring is provided with a herringbone groove structure matching the herringbone convex structure; the top of the pressure ring is provided with an arc surface structure protruding outward; the arc surface structure matches the arc groove provided at the bottom of the isolation ring.

[0011] Preferably, the outer diameter of the annular outer surface of the head ring is smaller than the inner diameter of the packing box; the inner surface of the head ring includes an annular protrusion structure with an arc-shaped cross-section and an annular step located below the annular protrusion structure; the inner diameter of the annular protrusion structure is smaller than the outer diameter of the plunger.

[0012] Preferably, the head ring contains evenly distributed fabric-reinforced elastic material; and the surface of the head ring is evenly sprayed with a layer of self-lubricating material protective film.

[0013] Preferably, the rubber material content of the head ring is in the range of 35% to 75%.

[0014] Preferably, the sealing ring is used in a cementing packing assembly of a cementing vehicle, and comprises a head ring, a pressure ring, and an isolation ring which are sequentially sleeved on a plunger.

[0015] Preferably, the sealing ring is used in a fracturing packing assembly of a fracturing vehicle, comprising one head ring and two pressure rings which are sequentially mounted on the plunger.

[0016] A method for manufacturing the self-lubricating high-pressure plunger pump sealing ring comprises the following steps:

[0017] S100. The rubber material and the fabric material are mixed in a preset ratio to form a fabric-reinforced rubber having fabric fibers;

[0018] S200. The fabric-reinforced rubber is cut obliquely into thin sheets so that the fabric fibers form an artificially preset deflection angle;

[0019] S300. Joining the fabric-reinforced rubber sheet, and then cutting the joined sheet into strip material; S400. Stacking or winding the strip material into a preform;

[0020] S500. The preform is placed in the mold cavity of the die, and the vulcanization conditions are set: the vulcanization temperature is 170° C., the vulcanization pressure is 15 MPa, and the vulcanization time is 20 min. According to the process requirements, the preform is pushed into the flat vulcanizer to vulcanize the preform to form the head ring;

[0021] S600. Trim the head ring after vulcanization, and then spray a layer of self-lubricating material protective film evenly on the surface of the head ring.

[0022] Preferably, the mixing process of the rubber material and the fabric material in step S100 is: calendering the rubber material and the fabric material together through a calender.

[0023] Preferably, the mixing process of the rubber material and the fabric material in step S100 is:

[0024] Sa100. The rubber material is dissolved in a solvent suitable for the chemical properties of a specific rubber, or an organic solvent or a plasticizer is used to convert the rubber material into a liquid or low-viscosity flowable state;

[0025] Sa200. The liquid rubber material is applied to the fabric material;

[0026] Sa300 heats the fabric material and the liquid rubber material to allow the rubber material to penetrate into the fabric material, thereby generating the solid fabric-reinforced rubber.

[0027] Preferably, the method for applying the liquid rubber material to the fabric material in step Sa200 is: spraying the liquid rubber material onto the fabric material; or using a transfer roller mechanism to apply the liquid rubber material onto a roller, and then transferring the liquid rubber material to the fabric material through the roller contacting the fabric material.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. Since the packing head ring of this patent is made of all-fabric reinforced rubber, its unique manufacturing process ensures that the fiber direction of the fabric reinforcement material is radially perpendicular to the movement axis of the plunger, which significantly enhances the shear strength of the contact area on the inner surface of the head ring.

[0030] 2. Because the aramid cloth material used in this patent has excellent wear resistance, tear resistance and corrosion resistance, it effectively improves the tear strength of the head ring, while reducing the friction coefficient and reducing the risk of leakage.

[0031] 3. The aramid cloth treated with liquid or low-viscosity flowable rubber used in this patent has good bonding properties, thus avoiding the problem of delamination or peeling between layers.

[0032] 4. Since this patent makes full use of the characteristics of the aramid cloth bevel structure in elastic deformation, the overall performance of the headband is enhanced.

[0033] 5. Since this patent is applicable to various models and specifications of fracturing and cementing head rings, it is easy to operate and does not require special equipment and process conditions, thereby improving practicality and convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic cross-sectional view of the arrangement of the cementing packing assembly of the present invention;

[0035] Figure 2 A schematic cross-sectional view of the arrangement of the fracturing packing assembly of the present invention;

[0036] Figure 3 It is a schematic cross-sectional view of the head ring of the present invention cut along a plane parallel to the plunger axis;

[0037] Figure 4 It is a schematic diagram of a head ring blank of the present invention;

[0038] Figure 5 It is a schematic diagram of the parting surface of the head ring forming mold of the present invention;

[0039] Figure 6 It is a cross-sectional view of the head ring of the present invention after being molded and protected.

[0040] Among them: 1. Head ring, 2. Pressure ring, 3. Isolation ring, 110. Herringbone convex structure, 120. Annular outer surface, 130. Inner surface, 131. Annular convex structure, 132. Annular step, 210. Herringbone groove structure, 220. Arc surface structure, 310. Arc groove DETAILED DESCRIPTION

[0041] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0042] like Figure 1 , 2 As shown in , 3, a self-lubricating high-pressure plunger pump sealing ring comprises a head ring 1, a pressure ring 2, and an isolation ring 3 which are sequentially sleeved on the plunger, wherein:

[0043] The top of the head ring 1 is provided with a herringbone convex structure 110 protruding outward; the bottom of the pressure ring 2 is provided with a herringbone groove structure 210 matching the herringbone convex structure 110; the top of the pressure ring 2 is provided with an arc surface structure 220 protruding outward; the arc surface structure 220 matches the arc groove 310 provided at the bottom of the isolation ring 3.

[0044] It should be noted that the outer diameter of the annular outer surface 120 of the head ring 1 is smaller than the inner diameter of the packing box to facilitate installation; the inner surface 130 of the head ring 1 includes an annular protrusion structure 131 with an arc-shaped cross-section and an annular step 132 located below the annular protrusion structure 131; the inner diameter of the annular protrusion structure 131 is smaller than the outer diameter of the plunger, thereby ensuring close contact with the plunger, improving sealing, and avoiding unnecessary shaking.

[0045] It should be further explained that the herringbone convex structure 110 at the upper end of the head ring 1 is provided with a convexity along the center line, and is closely matched with the herringbone groove structure 210 at the bottom of the pressure ring 2 to reduce relative movement; the annular step 132 at the lower end of the head ring 1 fits with the packing seat ring. This structure not only ensures the overall tightness of the packing assembly, but also effectively prevents high-hardness sand particles from invading the interior of the assembly, thereby reducing wear.

[0046] It should be further explained that the head ring 1 has greater elasticity than the pressure ring 2, and can maintain a constant force on the pressure ring 2 during assembly. When the packing nut is threadedly connected to the casing, the elasticity of the head ring 1 can compensate for small compression fluctuations, maintain a constant axial force on the pressure ring 2, and ensure the sealing effect.

[0047] It should be further explained that the headband 1 contains evenly distributed fabric-reinforced elastic material; and a layer of self-lubricating material protective film is evenly sprayed on the surface of the headband 1.

[0048] In this specific embodiment, the rubber material content of the headband 1 is in the range of 35% to 75%, preferably 55% to 65%.

[0049] like Figure 1 As shown, it should be noted that the sealing ring is used for a cementing packing assembly of a cementing vehicle, and comprises a head ring 1, a pressure ring 2, and an isolation ring 3 which are sequentially sleeved on the plunger.

[0050] like Figure 2 As shown, it should be noted that the sealing ring is also used for a fracturing packing assembly of a fracturing vehicle, which includes a head ring 1 and two pressure rings 2 which are sequentially sleeved on the plunger.

[0051] A method for manufacturing a self-lubricating high-pressure plunger pump sealing ring comprises the following steps:

[0052] S100. Mixing the rubber material and the fabric material in a manually preset ratio to form a fabric-reinforced rubber having fabric fibers.

[0053] S200. The fabric-reinforced rubber is cut obliquely into thin slices so that the fabric fibers form an artificially preset deflection angle.

[0054] S300. Joining the fabric-reinforced rubber sheets, and then cutting the joined sheets into strip-shaped materials.

[0055] S400. Stack or roll the strip material into a preform.

[0056] S500. Place the preform in the mold cavity of the die, set the vulcanization conditions: vulcanization temperature 170° C., vulcanization pressure 15 MPa, vulcanization time 20 min, push it into the flat vulcanizer according to the process requirements, and vulcanize the preform to form a head ring 1.

[0057] S600. Trim the head ring 1 after vulcanization, and then spray a layer of self-lubricating material protective film evenly on the surface of the head ring 1.

[0058] It should be noted that if Figure 4 The blank of the head ring 1 made of fabric-reinforced rubber shown is completely composed of evenly distributed fabric-reinforced elastic material and does not contain any other type of embedded or attached materials; the mixing process of the rubber material and the fabric material in step S100 is: calendering the rubber material and the fabric material together through a calender.

[0059] It should be further explained that in order to make the fabric-reinforced rubber into the head ring 1, the rubber material needs to be mixed with the fabric material; wherein the rubber material includes hydrogenated nitrile rubber. The rubber material can be smoothed and thinned by a roller through a calender together with the fabric material; thereby, the rubber content of the head ring 1 blank reaches the specification requirement of 35% to 75%; the optimal range of the rubber content of the head ring 1 blank is 55% to 65%.

[0060] It should be further explained that the mixing process of the rubber material and the fabric material in step S100 is:

[0061] Sa100. Dissolve the rubber material in a solvent suitable for the specific rubber chemistry, or use an organic solvent or plasticizer to convert the rubber material into a liquid or low viscosity flowable state.

[0062] Sa200. Apply liquid rubber material to the fabric material.

[0063] Sa300 heats the fabric material and the liquid rubber material, allowing the rubber material to penetrate into the fabric material, thereby generating a solid fabric-reinforced rubber.

[0064] It should be further explained that the method of applying the liquid rubber material to the fabric material in step Sa200 is: spraying the liquid rubber material onto the fabric material, which can be done by using pneumatic spraying equipment or airless spraying machines, or using a transfer roller mechanism, applying the liquid rubber material onto a roller, and then transferring the liquid rubber material onto the fabric material through the roller contacting the fabric material. When using a roller, the coating weight can be controlled by changing the relationship between the roller speed and the fabric speed.

[0065] It should be further explained that after the coating in step Sa300 is completed, the rubber is placed in an oven to remove the solvent or gel the rubber, thereby producing a solid fabric-reinforced rubber.

[0066] like Figure 5 As shown, it should be noted that the compression mold in step S500 includes a first mold component A, a second mold component B, and a third mold component C, which together define the shape of the mold cavity. By applying pressure to the first mold component A, the second mold component B, and the third mold component C, the fabric-reinforced rubber is forced to be in close contact with all areas in the mold cavity. The fabric-reinforced rubber is molded into a finished product shape to form a head ring 1.

[0067] like Figure 6 As shown, it should be noted that in step S600, the quality of the vulcanized head ring 1 is checked, and a layer of self-lubricating material protective film with a thickness of 40-100 μm is sprayed on the surface of the head ring 1 that meets the specifications to provide additional protection.

[0068] The head ring 1 after the protective treatment of spraying the self-lubricating material protective film has the following advantages:

[0069] 1. The surface is smooth, without defects, bubbles or cracks.

[0070] 2. The size meets the requirements, without deformation or delamination.

[0071] 3. The bonding strength reaches more than 12MPa, with good adhesion and not easy to peel off or slip.

[0072] 4. The friction coefficient is reduced, and the tear strength and corrosion resistance are improved.

[0073] It should be noted that the technical problem addressed by the present invention is to improve the wear resistance, tear resistance and corrosion resistance of the packing head rings of fracturing pumps and cementing pumps in oil and gas production equipment. In the fracturing and cementing operations of oil and gas wells, the packing head rings in the pumping system need to withstand the wear of high-hardness sand particles under high-pressure environments, as well as the corrosion and wear of fracturing fluids with high acidity, low viscosity and poor self-lubrication. Therefore, the technical field of the present invention also includes providing a packing head ring that can maintain better wear resistance, tear resistance and corrosion resistance under the above-mentioned harsh working conditions, thereby extending the service life of the packing assembly, reducing the frequency of equipment maintenance and replacement, and improving oil and gas production efficiency and economic benefits.

[0074] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0075] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0076] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0077] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A self-lubricating high-pressure plunger pump sealing ring, characterized in that: It comprises a head ring (1), a pressure ring (2), and an isolation ring (3) which are sequentially mounted on a plunger, wherein: The top of the head ring (1) is provided with a herringbone convex structure (110) protruding outward; the bottom of the pressure ring (2) is provided with a herringbone convex structure (210) matching the herringbone convex structure (110); the top of the pressure ring (2) is provided with an arc surface structure (220) protruding outward; the arc surface structure (220) matches the arc-shaped groove (310) provided at the bottom of the isolation ring (3).

2. The self-lubricating high-pressure plunger pump sealing ring according to claim 1, characterized in that: The outer diameter of the annular outer surface (120) of the head ring (1) is smaller than the inner diameter of the packing box; the inner surface (130) of the head ring (1) comprises an annular protrusion structure (131) with an arc-shaped cross section and an annular step (132) located below the annular protrusion structure (131); the inner diameter of the annular protrusion structure (131) is smaller than the outer diameter of the plunger.

3. The self-lubricating high-pressure plunger pump sealing ring according to claim 1, characterized in that: The head ring (1) comprises evenly distributed fabric-reinforced elastic material; and a layer of self-lubricating protective material film is evenly sprayed on the surface of the head ring (1).

4. The self-lubricating high-pressure plunger pump sealing ring according to claim 3, characterized in that: The rubber material content of the head ring (1) is in the range of 35% to 75%.

5. The self-lubricating high-pressure plunger pump sealing ring according to any one of claims 1 to 4, characterized in that: The sealing ring is used for a cementing packing assembly of a cementing vehicle, and comprises a head ring (1), a pressure ring (2), and an isolation ring (3) which are sequentially sleeved on a plunger.

6. The self-lubricating high-pressure plunger pump sealing ring according to any one of claims 1 to 4, characterized in that: The sealing ring is used for a fracturing packing assembly of a fracturing vehicle, and comprises a head ring (1) and two pressure rings (2) which are sequentially sleeved on a plunger.

7. A method for manufacturing the self-lubricating high-pressure plunger pump sealing ring according to any one of claims 1 to 4, characterized in that: The following steps are involved: S100. The rubber material and the fabric material are mixed in a preset ratio to form a fabric-reinforced rubber having fabric fibers; S200. The fabric-reinforced rubber is cut obliquely into thin sheets so that the fabric fibers form an artificially preset deflection angle; S300. Joining the fabric-reinforced rubber sheet, and then cutting the joined sheet into strips of material; S400. Stacking or winding the strip material into a preform; S500. The preform is placed in the mold cavity of the die, the vulcanization conditions are set, and the preform is pushed into the flat vulcanizer according to the process requirements to vulcanize the preform to form the head ring (1); S600. Trimming the head ring (1) after vulcanization, and then spraying a layer of self-lubricating protective material film evenly on the surface of the head ring (1).

8. The method for manufacturing a self-lubricating high-pressure plunger pump sealing ring according to claim 7, characterized in that: The mixing process of the rubber material and the fabric material in step S100 is: calendering the rubber material and the fabric material together through a calender.

9. The method for manufacturing a self-lubricating high-pressure plunger pump sealing ring according to claim 7, characterized in that: The mixing process of the rubber material and the fabric material in step S100 is: Sa100. The rubber material is dissolved in a solvent suitable for the chemical properties of a specific rubber, or an organic solvent or a plasticizer is used to convert the rubber material into a liquid or low-viscosity flowable state; Sa200. The liquid rubber material is applied to the fabric material; Sa300 heats the fabric material and the liquid rubber material to allow the rubber material to penetrate into the fabric material, thereby generating the solid fabric-reinforced rubber.

10. The method for manufacturing a self-lubricating high-pressure plunger pump sealing ring according to claim 9, characterized in that: The method for applying the liquid rubber material to the fabric material in step Sa200 is: spraying the liquid rubber material onto the fabric material; or using a transfer roller mechanism to apply the liquid rubber material onto a roller, and then transferring the liquid rubber material to the fabric material by contacting the roller with the fabric material.

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